10
In the “
Alarm
”
page it is possible to enable or disable the phase loss, neutral loss, phase
sequence and measurements out of range priority alarms.
Considering phase loss alarm, s
elect the “
Phase Loss Threshold
“
in the range: 60 to 90% of the
rated voltage set in the
page “GRID TYPE”
.
The percentage of the phase loss threshold is related to the detection of the regenerated
voltage on the lost phase.
The regenerated voltage has a lower value than the rated voltage, in particular:
•
in delta system the regenerated voltage is up to 85% of the rated voltage,
•
in star system the regenerated voltage is up to 70% of the rated voltage.
The recommended pre-set value is 85% for delta voltages.
Setting the threshold below 85% can cause insensitivity to the regenerated voltage, while
setting the threshold above 85% can cause excessive sensitivity to small network variations.
Considering neutral loss alarm, s
elect the “
Neutral Loss Threshold
“
in the range: 10 to 30% of
the rated voltage set in the
page “GRID TYPE”
.
The percentage of the neutral loss threshold is related to the "distance" between the real
position of the neutral within delta voltages and the position in which it should be, i.e. at the
center of the delta voltages.
Considering measurements out of range alarm, DPD02 performs three measurements, each of
which has a validity range.
1.
Voltage:
➢
delta voltages, 208V-40% to 480V+15% (125V to 552V)
➢
star voltages, 120V-40% to 277V+15% (72V to 318V)
2.
Frequency: 50Hz-10% to 400Hz+10% (45Hz to 440Hz)
3.
Asymmetry: 0 to 30%
